Woman who is allergic to her husband's sperm opens up about rare condition that threatened to destroy their sex life

'All of a sudden instead of living with your new wife or husband, you are more like roommates'

Intimacy killer: A woman with seminal plasma hypersensitivity has opened up about how is allergic to her husband's sperm - which affects up to 40,000 women in the U.S.

A newlywed bride, who waited until she was married to have sex with her husband, has opened up about the shock discovery that she is allergic to his sperm.

Clara, 35, has seminal plasma hypersensitivity, an allergic reaction to the proteins in her husband Jeff's semen - and even using a condom won't help the North Carolina couple.

'I had this bizarre reaction,' Clara told ABC, who for privacy reasons did not want to use her real name. 'I had burning and swelling and redness, which was very unusual. I thought I had contracted an STD.'

After several visits to the gynecologist and and hours of research online, the couple finally got some answers, but it threatened to destroy their sex life after they had no choice but to avoid intimacy.

Jeff explained: 'It was a real problem, because everything else was great. We were madly in love, but it was a real game-changer for a while.

'It pretty much dramatically reduced our libido. We really haven't had much sex at all for the last 10 months. The intimacy level drops dramatically -- all of a sudden instead of living with your new wife or husband, you are more like roommates.'

Cara, who was also experiencing yeast infections from her hypersensitivity, agreed: 'In a normal romantic relationship, you want to feel attractive to your partner and want to do things that make you feel sexy.

'I feel like we actually started to define ourselves -- minimizing things to avoid sex. I started thinking I wouldn't wear sexy underwear. What seemed like medical problems had bigger effects.'

Up to 40,000 women in the U.S. suffer from seminal plasma hypersensitivity, which does not affect fertility, according to Dr. Jonathan Bernstein, a professor at the University of Cincinnati, who specializes in allergies and immunology.

Women can experience a breakout of hives, abdominal swelling or a reaction that they describe as 'like a needle sticking in to their vagina,' according to Dr Bernstein.

Cara, who said the allergic reaction had never happened before in previous relationships, explained: 'The swelling was worst immediately after sex. It would take 24 hours to subside and my skin would be irritated as if you'd put a chemical on it that caused it to burn.

'It was almost raw and took a while to heal.'

Dr. Andrew Goldstein, director of the Centers for Vulvovaginal Disorders in Washington, D.C. and New York City, said the condition is so uncommon, he has only treated 'about a dozen' cases in the last ten years.

Often, women don't get an accurate diagnosis because the condition can be confused with yeast and vaginal infections.

But once a diagnosis is made, treating semen allergies is relatively painless.

A doctor will isolate the proteins in the man and carry out skin testing on the woman to determine which proteins are to blame. Then, the woman is desensitized to the allergen.

Just two weeks ago, Clara underwent this intravaginal 'graded challenge' using dilutions of her husband's seminal fluid which were injected every 15-20 minutes over the course of two to three hours.

The couple had to have sex within 12 hours to test Cara's desensitization. Her symptoms 'resolved substantially,' according to Dr Bernstein, who had treated the couple.

Cara said: 'There was a small amount of swelling, but compared to previous times, it was much less.'

The couple were asked to have sex every few days 'to see how it went,' explained Cara, adding that each time went well.

'Now I am interested in having sex again,' she said.

Jeff said his wife's treatment has been 'a very hopeful experience'.

He explained: 'On a number of levels, it's been restorative. A whole side of our relationship really suffered. Now it's a whole new world.' WHAT IS SEMINAL PLASMA HYPERSENSITIVITY?

Seminal plasma hypersensitivity causes an allergic reaction to the proteins carrying the sperm, not the sperm itself Between 20,000 to 40,000 women in the U.S. may experience the allergy Symptoms include swelling of the vagina, itching, burning and painful blistering of the vagina and surrounding area The allergic reaction can last anywhere from 20 minutes to more than a day A typical patient is a woman having intercourse for the first time with a partner It can also develop after having sex with the same partner for a long time It can occur after a period of abstinence, such as when a couple resumes having sex following pregnancy and childbirth Seminal plasma hypersensitivity is often mistaken for other vaginal conditions, such as a yeast infection or herpes